Position sensitive detector based image conversion system capable of preserving subpixel information

Abstract

An image detection and pixel processing system includes a plurality of position sensitive detector elements arranged to receive an image. Each position sensitive detector element provides information for determining both a total light intensity value within the position sensitive detector element and a centroid of light intensity indicative of light intensity position within the position sensitive detector element. An image processing assembly receives information from the plurality of position detector elements with the image processing assembly relating a pixel and its encompassed subpixel area to each corresponding position detector element. The total light intensity within the pixel and the centroid of light intensity within the subpixel is determined, with the image processing assembly rendering each subpixel area as an edge when magnitude of the centroid of light intensity is large.

The claimed invention is: 
     
       1. An image detection and pixel processing system comprising a plurality of position sensitive detector elements arranged to receive an image, with each position sensitive detector element providing information for determining both a total light intensity value within the position sensitive detector element and a centroid of light intensity indicative of light intensity position within the position sensitive detector element, and   an image processing assembly connected to receive information from the plurality of position detector elements, the image processing assembly relating a pixel and its encompassed subpixel area to each corresponding position detector element, and further determining the total light intensity within the pixel and the centroid of light intensity within the subpixel area, with the image processing assembly rendering each subpixel area as an edge when magnitude of the centroid of light intensity is large, and wherein the image processing assembly renders the subpixel area as an edge by finding a first gray value on a first side of the edge, determining actual edge position, and using actual edge position and the first gray value to determine a second gray value on a second side of the edge opposite the fist side of the edge.   
     
     
       2. The image detection and pixel processing system of claim 1, wherein determining actual edge position further comprises partially determining parameterization of the edge using gray-on-gray moments, and converting gray-on-gray moments to gray-on-black to uniquely define edge location. 
     
     
       3. The image detection and pixel processing system of claim 2, wherein partially determining parameterization of the edge using gray-on-gray moments further comprises use of lookup tables generated to map moments of the centroid of light intensity onto an edge parameter. 
     
     
       4. The image detection and pixel processing system of claim 1, wherein finding the first gray value is determined using context of an adjacent position sensitive detector element. 
     
     
       5. The image detection and pixel processing system of claim 1, wherein finding the first gray value is an estimate based on interpolation of gray values of two adjacent position sensitive detector elements. 
     
     
       6. The image detection and pixel processing system of claim 1, wherein the image processing assembly renders the subpixel area as an edge when the magnitude of the centroid of light intensity is greater than about 1/3. 
     
     
       7. An image processing method using information obtained from a plurality of position sensitive detector elements arranged to receive an image, the method comprising the steps of determining a total light intensity value within each of said position sensitive detector elements,   determining a centroid of light intensity indicative of light intensity position within each of said position sensitive detector elements,   relating a pixel and its encompassed subpixel area to each of said corresponding position detector element to determine the total light intensity within the pixel and the centroid of light intensity within the subpixel area, and   rendering each subpixel area as an edge when magnitude of the centroid of light intensity is large, and evaluating the subpixel area to determine an edge, finding a first gray value on a first side of the edge, determining actual edge position, and using actual edge position and the first gray value to determine a second gray value on a second side of the edge opposite the first side of the edge.   
     
     
       8. The image processing method of claim 7, wherein the step of determining actual edge position further comprises the steps of partially determining parameterization of the edge using gray-on-gray moments, and converting gray-on-gray moments to gray-on-black to uniquely define edge location. 
     
     
       9. The image processing method of claim 8, wherein the step of partially determining parameterization of the edge using gray-on-gray moments further comprises the step of mapping moments of the centroid of light intensity onto an edge parameter using generated lookup tables. 
     
     
       10. The image processing method of claim 7, wherein the step of finding the first gray value further comprises the step of evaluating gray value context of an adjacent position sensitive detector element. 
     
     
       11. The image processing method of claim 7, wherein the step of finding the first gray value further comprises the step of estimating gray value context based on interpolation of gray values of two adjacent position sensitive detector elements.